I’ve heard countless excuses for why people don’t want to lift heavy (or heavier). Women often times don’t want to get “bulky.” Bodybuilders don’t want to lose mass. Cross-fitters and endurance athletes don’t want to compromise performance or stamina. The list goes on. But the bottom line is that heavy lifting (1-6 reps max.) has just as many benefits as other exercise styles and will not compromise your size or stamina. So here are my top reasons for lifting heavy and how I incorporate it into my workout regimen.

1. Prevent plateau*

Most of us have one or two favorite styles of exercise. For me, its yoga and lifting in the 8-12 rep range. Some people enjoy lifting 15+ reps, others would choose running over lifting any day, and still others prefer bootcamp-style high intensity interval training. Whatever your poison, adding in a phase of heavy lifting can increase strength and promote better results. One of the main reasons is that, when it comes to results, doing the same type of exercise all the time leads to diminishing returns. Our bodies adapt pretty quickly to whatever exercise we’re doing, becoming more and more efficient and needing to change less and less to do the same movement. When our body stops changing in response to the exercise, we say we’ve “hit a plateau.”

Adding in a phase of heavy lifting by performing 2-5 reps of a given exercise at the maximum weight that you can lift for those reps will shock your body into work mode and stimulate impressive changes (some of which are discussed below).

*Note: this is assuming that you are not already lifting in the 1-6 rep range and are not a powerlifter.

2. Get stronger

Our bodies adapt to the specific stresses we place on them. This allows us to become more efficient at whatever task we’re facing. Just think about any new activity you do – at first it’s hard, maybe a little awkward, and takes a long time. The more you practice the activity, the better and faster you get at accomplishing it. The same goes for building strength. By training specifically for strength, we get stronger.

Aside from developing more or bigger muscle, we also gain strength from enhancing intramuscular coordination. When we move, our brain recruits muscles in whatever body part we’re moving, but our brain does not typically recruit the entire muscle. Muscles are broken up in motor units, and each motor unit contains muscle fibers and a motor neuron that innervates the muscle fibers. One muscle can consist of multiple motor units. The strength or force of a muscle contraction depends on how many motor units are recruited together at the same time. The more motor units that contract together, the greater the force produced by the contraction. Strength training with heavy weights teaches the body to activate more motor units synchronously thereby increasing the amount of force or strength the muscle can produce.

3. Get stronger without getting (much) bigger – for women

First, I want to reiterate what every fitness professional and blog has said a billion-gazillion times because its true — women, it is extremely difficult for you to bulk up “like a man” no matter how much weight you lift or how many reps you do. It just isn’t going to happen without a very specific training and diet program. Even then it will be difficult without supplements and testosterone boosters. The fact of the matter is, women have only a fraction of the amount of free testosterone as men have, and testosterone is essential for gaining mass.

The types of muscle fibers in our bodies are grouped into three categories:

Type I fibers: small in circumference, slow to fatigue, the kind used primarily for aerobic activity

Type II fibers: large in circumference, quick to fatigue, used primarily for anaerobic activity, and

A third type sometimes called Type IIA or Type X fibers which fall in between Type I and Type II and are thought to exhibit more Type I or Type II properties depending on the type of training you do.

One theory as to why 1-6 rep training will not build as much mass as 10-15 rep training is that 1-6 rep training recruits only Type II fibers, whereas because 10-15 rep training typically goes to fatigue, it recruits both Type II and Type I fibers. This means that 10-15 rep training recruits more muscle fibers overall, which in turn causes more growth. On the other hand, 1-6 rep training focuses on one specific category of muscle fibers and therefore recruits less muscle fibers overall, which in turn results in less overall growth. As a corollary, it is also theorized that 10-15 rep training produces a greater increase in number of mitochondria (cells’ energy powerhouses) than 1-6 rep training, which in turn leads to greater growth in size.

Another theory is that the different lifting styles cause different types of muscle growth. Some experts theorize that 10-15 rep training causes primarily sarcoplasmic hypertrophy, or growth of the fluid surrounding muscle fibers which causes the muscle to grow larger in size. These experts also theorize that 1-6 rep training primarily increases the number of contractile proteins in muscle fibers, i.e. myofibril hypertrophy. This causes the muscle fiber to get thicker relative to the sarcoplasm surrounding it, but the muscle stays the same, or close to the same, size. The theory of sarcoplasmic v. myofibril hypertrophy is hotly debated in the fitness industry.

Regardless of which theory you subscribe to, or the exact cause, both styles will promote muscle growth and development, but 10-15 rep training is known to dramatically increase muscle size (particularly, high volume training) when compared to 1-6 rep training.

5. Reduce your biological age

Heavy lifting increases muscle mass and improves bone density — two things we tend to lose as we age and that are directly linked to your biological age (as well as other things like injury, chronic disease, and early death). Heavy lifting also stimulates protective hormones like testosterone and growth hormone, both of which are important for repairing and developing muscle.

6. Prevent injury

Heavy lifting strengthens bones and connective tissues that often get overused in highly repetitive activities like lighter weightlifting and running. Strengthening the connective tissues in joints and between muscles and bones helps prevent degeneration that results from overuse and reduces your risk of injury.

7. Burn more fat and boost metabolism

Just like with high intensity aerobic exercise, you will burn significantly more calories in less time with heavy lifting than with lightweight lifting. This means more fat burn and faster results. Also like high intensity exercise, your body will continue to burn more calories for much longer after heavy lifting than light lifting. This is because heavy lifting recruits Type II fibers, which tap into your body’s fat stores and stimulate fat burning hormones that continue to burn fat for up to 8 hours after your workout. Lightweight lifting (>15 reps) burns extra calories for only about an hour after your workout.

In addition to increased during- and after- burn, heavy lifting can increase resting metabolism, meaning your body will burn more calories just doing nothing. Muscle burns about 5-7 calories per day at rest. By adding just 5 pounds of muscle, you can increase your metabolism by 25-35 calories per day. This may not sound like a lot, but that’s an extra 175-245 calories per week or 9,125-12,775 calories per year! In other words, that’s 2.6-3.65 pounds per year of weight loss or prevented weight gain. When you consider that we, on average, gain 10 pounds per decade after turning 20 years old, the small increase in metabolism by adding more muscle becomes significant.

8. Improve endurance

Despite what many endurance athletes may think, strength training actually improves endurance, speed, performance, and running economy – meaning more strength allows you to do more with less energy and effort.

9. Train your brain

Heavy lifting strengthens not just your muscles, but your brain too, meaning improved cognitive functioning especially as we age. Studies have linked muscle power (developed through strength training) to healthy cognitive aging. A 2012 study also found that the heaviest weight lifting (95% of 1RM) tapped into unique brain regions not trained by 10 rep or lightweight training.

10. Increase confidence

Strength training has been associated with increased confidence and feelings of happiness as well as reduced anxiety and depression. Trust me, there’s nothing like feeling strong and accomplished after a hard, heavy lifting session!!

How to incorporate heavy lifting into your program

Ok, so now you’re probably thinking, well heavy lifting sounds great, but how do I fit it in to what I’m already doing? As I’m sure you already know, varying your workouts helps prevent plateau and get better, faster results. The consensus is that you should switch up your training style about every 4-8 weeks. Depending on your goals, you can cycle in a 4-8 week heavy lifting phase once a year up to every few weeks. Another way I like to incorporate heavy lifting is to designate one training day per week to lifting in the 1-6 rep range. This method is more of a maintenance technique though. So if you’re looking to drop body fat or significantly increase strength, I recommend the first option with 2-4 days of heavy lifting per week.